本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

# 使用 `.` 標記法篩選陣列
<a name="filtering-with-dot"></a>

在下列範例中，使用點`.`符號從 AWS CloudTrail 日誌資料表的 `userIdentity` 欄中選取 `accountId` 欄位。如需詳細資訊，請參閱[查詢 AWS CloudTrail 日誌](cloudtrail-logs.md)。

```
SELECT
  CAST(useridentity.accountid AS bigint) as newid
FROM cloudtrail_logs
LIMIT 2;
```

此查詢會傳回：

```
+--------------+
| newid        |
+--------------+
| 112233445566 |
+--------------+
| 998877665544 |
+--------------+
```

若要查詢值陣列，請發出此查詢：

```
WITH dataset AS (
  SELECT ARRAY[
    CAST(ROW('Bob', 38) AS ROW(name VARCHAR, age INTEGER)),
    CAST(ROW('Alice', 35) AS ROW(name VARCHAR, age INTEGER)),
    CAST(ROW('Jane', 27) AS ROW(name VARCHAR, age INTEGER))
  ] AS users
)
SELECT * FROM dataset
```

它會傳回此結果：

```
+-----------------------------------------------------------------+
| users                                                           |
+-----------------------------------------------------------------+
| [{NAME=Bob, AGE=38}, {NAME=Alice, AGE=35}, {NAME=Jane, AGE=27}] |
+-----------------------------------------------------------------+
```